Photoelectron satellites—the structures appearing on the low kinetic or high binding-energy side of the “main” or “elastic” photopeak—betray the complex many-body interactions set in motion by the sudden creation of the core hole. In this work, we demonstrate, using the technologically important ferromagnetic half-metal ${\mathrm{CrO}}_2$, how such satellites can manifest themselves in other core-level spectroscopies of the material and how they can reveal important details pertinent to its electronic structure. Specifically, we identify a fluorescence satellite in the Cr $L_3$ resonant x-ray-emission spectra that radiates at a constant emission energy across the Cr $L_3$ x-ray edge with energy ≈1.3 eV above the ordinary valence fluorescence. We provide evidence that this feature arises from the valence recombination of the Cr $2p$ core hole “dressed” by the same shakeup charge-transfer process present in both the Cr x-ray photoelectron and the Cr x-ray absorption spectra with its energy uniquely measuring the exchange splitting of the Cr $3d$ level. Further analysis of the x-ray emission data reveals three additional features that radiate at constant loss energy that are attributed to combinations of Cr $3d\left(t_{2g}\right)$ → Cr $3d\left(t_{2g}\right)$, charge-transfer O $2p\to \mathrm{Cr}$ $3d$, and crystal-field $\mathrm{Cr}3d\left(t_{2g}\right)\to \mathrm{Cr}3d\left(e_g\right)$ excitations. These assignments and their energies are supported by density-functional theory calculations, the accuracy of which we demonstrate by hard x-ray valence-photoemission measurements. Atomic multiplet calculations, which include crystal-field effects, help interpret x-ray photoelectron and x-ray absorption spectra of the covalently mixed Cr ion. Resonant Cr K-$L_{2,3}{L}_{2,3}$ Auger-electron emission spectra support a ligand-to-metal nature of the charge-transfer process while highlighting the charge sensitivity differences between photon-in/electron-out and photon-in/photon-out spectroscopies.

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• Density of states
• Electronic structure
• Magnetism
• Ferromagnets
• Half-metals
• Band structure methods
• Crystal-field theory
• Density functional theory
• Hard x-ray photoelectron spectroscopy
• X-ray absorption spectroscopy
• X-ray photoelectron spectroscopy
• X-ray scattering